1. Field of the Invention
The present invention relates to a radiation detection apparatus, and more particularly to a real-time self-networking radiation detector apparatus for use with cargo shipments.
Cargo vessels (e.g., ships or other vessels) approaching the United States may be carrying nuclear explosive devices, radiological dispersal devices or bulk materials from which such devices could be manufactured after import to the U.S. This apparatus would equip cargo containers of approaching vessels with radiation detection equipment. A friendly vessel could request remote inspection as it approaches port; alternatively inspection could be initiated from a US marine/land-based control center. A shutdown of major ports due to a threat of an attack could result in high costs, particularly for those economies more reliant on trade.
If cargo vessels were inspected only from above the waterline from surface vessels or aircraft, radioactive contraband might be concealed by placing it in the center of the vessel near its bottom. With real-time communications and analysis of data, scans could be repeated to confirm previous findings and reduce false alarms. Radiation measurements would be recorded relative to the position on the ship. The pattern of radiation, particularly if cargo manifest is also available, may further help to distinguish contraband from legitimate cargo that contains traces of radioactive materials, e.g., ceramic tile, potassium-containing fertilizer.
2. Description of the Prior Art
U.S. Pat. No. 4,613,758 to Ing, et al., which is incorporated herein by reference, discloses direct reading detector/dosimeter for neutrons and other high LET radiation is described, comprising a selected, substantially transparent, elastic solid medium uniformly impregnated with droplets of an immiscible detector liquid. The detector liquid-in-solid is appropriately confined and rendered stable for storage by adding a layer of excess detector liquid and sealing in a container. On opening the container and removing the excess detector liquid, the detector liquid droplets become superheated and the detector/dosimeter is activated. Neutrons and other high LET radiation will trigger the vaporization of the superheated droplets and the selected elastic, solid medium will trap the products of vaporization and retain a visual record thereof over an extended time. The number of vaporization events can be counted to give a measure of the radiation dose.